/*
 * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
 *
 * This software is open source.
 * See the bottom of this file for the licence.
 */

package org.dom4j.io;

import org.dom4j.Element;
import org.dom4j.ElementHandler;
import org.dom4j.ElementPath;

/**
 * <p> <code>ElementStack</code> is used internally inside the {@link
 * SAXContentHandler} to maintain a stack of {@link Element}instances. It opens
 * an integration possibility allowing derivations to prune the tree when a node
 * is complete. </p>
 * 
 * @author <a href="mailto:james.strachan@metastuff.com">James Strachan </a>
 * @version $Revision: 1.2 $
 */
class ElementStack implements ElementPath
{
   /** stack of <code>Element</code> objects */
   protected Element[] stack;

   /** index of the item at the top of the stack or -1 if the stack is empty */
   protected int lastElementIndex = -1;

   private DispatchHandler handler = null;

   public ElementStack()
   {
      this(50);
   }

   public ElementStack(int defaultCapacity)
   {
      stack = new Element[defaultCapacity];
   }

   public void setDispatchHandler(DispatchHandler dispatchHandler)
   {
      this.handler = dispatchHandler;
   }

   public DispatchHandler getDispatchHandler()
   {
      return this.handler;
   }

   /**
    * Peeks at the top element on the stack without changing the contents of the
    * stack.
    */
   public void clear()
   {
      lastElementIndex = -1;
   }

   /**
    * Peeks at the top element on the stack without changing the contents of the
    * stack.
    * 
    * @return the current element on the stack
    */
   public Element peekElement()
   {
      if(lastElementIndex < 0)
      {
         return null;
      }

      return stack[lastElementIndex];
   }

   /**
    * Pops the element off the stack
    * 
    * @return the element that has just been popped off the stack
    */
   public Element popElement()
   {
      if(lastElementIndex < 0)
      {
         return null;
      }

      return stack[lastElementIndex--];
   }

   /**
    * Pushes a new element onto the stack
    * 
    * @param element DOCUMENT ME!
    */
   public void pushElement(Element element)
   {
      int length = stack.length;

      if(++lastElementIndex >= length)
      {
         reallocate(length * 2);
      }

      stack[lastElementIndex] = element;
   }

   /**
    * Reallocates the stack to the given size
    * 
    * @param size DOCUMENT ME!
    */
   protected void reallocate(int size)
   {
      Element[] oldStack = stack;
      stack = new Element[size];
      System.arraycopy(oldStack, 0, stack, 0, oldStack.length);
   }

   // The ElementPath Interface
   //
   public int size()
   {
      return lastElementIndex + 1;
   }

   public Element getElement(int depth)
   {
      Element element;

      try
      {
         element = (Element) stack[depth];
      }
      catch(ArrayIndexOutOfBoundsException e)
      {
         element = null;
      }

      return element;
   }

   public String getPath()
   {
      if(handler == null)
      {
         setDispatchHandler(new DispatchHandler());
      }

      return handler.getPath();
   }

   public Element getCurrent()
   {
      return peekElement();
   }

   public void addHandler(String path, ElementHandler elementHandler)
   {
      this.handler.addHandler(getHandlerPath(path), elementHandler);
   }

   public void removeHandler(String path)
   {
      this.handler.removeHandler(getHandlerPath(path));
   }

   /**
    * DOCUMENT ME!
    * 
    * @param path DOCUMENT ME!
    * 
    * @return true when an <code>ElementHandler</code> is registered for the
    *         specified path.
    */
   public boolean containsHandler(String path)
   {
      return this.handler.containsHandler(path);
   }

   private String getHandlerPath(String path)
   {
      String handlerPath;

      if(this.handler == null)
      {
         setDispatchHandler(new DispatchHandler());
      }

      if(path.startsWith("/"))
      {
         handlerPath = path;
      }
      else if(getPath().equals("/"))
      {
         handlerPath = getPath() + path;
      }
      else
      {
         handlerPath = getPath() + "/" + path;
      }

      return handlerPath;
   }
}

/*
 * Redistribution and use of this software and associated documentation
 * ("Software"), with or without modification, are permitted provided that the
 * following conditions are met:
 * 
 * 1. Redistributions of source code must retain copyright statements and
 * notices. Redistributions must also contain a copy of this document.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * 
 * 3. The name "DOM4J" must not be used to endorse or promote products derived
 * from this Software without prior written permission of MetaStuff, Ltd. For
 * written permission, please contact dom4j-info@metastuff.com.
 * 
 * 4. Products derived from this Software may not be called "DOM4J" nor may
 * "DOM4J" appear in their names without prior written permission of MetaStuff,
 * Ltd. DOM4J is a registered trademark of MetaStuff, Ltd.
 * 
 * 5. Due credit should be given to the DOM4J Project - http://www.dom4j.org
 * 
 * THIS SOFTWARE IS PROVIDED BY METASTUFF, LTD. AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL METASTUFF, LTD. OR ITS CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 * 
 * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
 */
